Mohammad Sadegh Norouzi Nazar - Faculty of Engineering, University of Sistan and Baluchestan, Daneshgah Boulevard , Zahedan, Sistan and Baluchestan Province, Iran
Zahra Asadolahi - Faculty of Agriculture and natural recources, Lorestan University, P.O. Box ۴۶, Khorram Abad, Lorestan Provice, Iran
Fatemeh Rabbani - Faculty of Geography, University of Tehran, Enghelab street, Tehran, Tehran Province, Iran

Understanding the influence of climate change on water resources is of significance to solve the management problems of watersheds. In this study, we calibrated and validated the Soil and Water Assessment Tool (SWAT) using monthly observed discharge from 2001 to 2015 to quantify the impact of climate change on spatial distribution of blue and green water in a small river catchment in Northern Iran. The downscaled daily precipitation and temperature using the ECHAM5 projection data from CMIP3 under three SRES emission scenarios were used to construct future climate scenarios for periods of 2011-2032 and 2046-2065. According to the climate scenarios, the study catchment will experience an increase in precipitation, blue water and green water flow in future. The results of green water resource projections are different from subbasin to subbasin and among different scenarios. These results imply the large impact of climate change on water of the region and reveal the importance of further climate change analysis.

SWAT, Lars-WG, ECHAM5, Hydrological modeling, Emission scenario